Analysis of mutual influence of rotors in multi-motor assembly

Electric motor influences its surroundings by stray magnetic fields. This influence does matter in certain cases hence reduction of the field intensity outside the motor is a part of the motor design. The primary objective is to provide a safety region for humans, reduce a low-frequency electromagnetic emission, or produce magnetically silent electrical machines for propulsion of some military or oceanographic ships where low magnetic stray fields are required. This paper analyses the particular case of influence of stray magnetic fields of a motor in the multi-motor assembly of several stepper motors. The rotor position of each motor is affected by stray magnetic fields of nearby motors. Finite element analysis of mutual influence is provided, and construction change is suggested to reduce the position shift of the rotor due to the rotation of neighbouring rotors.